The device shown in FIG. 9 a semiconductor package generally of the type to which the present invention relates. The package comprises a generally rectangular body portion 12 and a plurality of leads 20 extending from the sides of the body portion and which are of a Z-shaped configuration, commonly referred to as "Z-shaped gull winged leads". These packages are presently manufactured by bending the leads to the Z-shaped configuration shown. The leads 20 must be within two working accuracies. One is the so-called "lead co-planarity" and the other is "lead skew". Lead co-planarity means the scattering of each lead 20 in the vertical direction, as represented by arrow A in FIG. 9, or said another way, the free terminal ends of the leads are defined as being co-planar when they all lie in a common plane P--P. Lead skew means the amount of distortion of the leads 20 in the transverse direction, as represented by arrow B in FIG. 9. Ideally, the spacing between adjacent leads for all of the leads 20 is within a predetermined, precise range.
Presently, the leads 20 are formed by clamping them between a forming die and a punch which is then reciprocated to bend the leads to the Z-shaped configuration. It has been found that this method requires a relatively high pressing force to secure lead co-planarity and that this high force adversely effects the lead skew, or lead to lead tolerance. Conversely, when the pressing force is decreased in an attempt to maintain the lead to lead tolerance and minimize lead skew, the lead co-planarity is adversely affected. Thus the conventional bending apparatus presently used for making semiconductor packages of this type is unsatisfactory since securing lead co-planarity is incompatible with minimizing lead skew.